This great little plant gets its common name from another species altogether: from the water cresses of the Nasturtium (mustard) family. The word is from the Latin nasus tortus, twisted nose, referring to the sharp taste of the leaves. Tropaeolum comes from the Latin word tropæum, a trophy, referring to the shape of the flowers; majus is from maior, Latin for ‘larger’.

The nasturtium is a fast-growing annual from Peru. It has pale green, umbrella-shaped leaves with long stems. Flowers are produced in summer and autumn and come in shades of orange, red, and yellow. There are trailing and bushy types, with single, semi-double or double flowers.

It is an ideal flower for a child’s first garden. The seeds are large and easily handled, and can be planted directly into the growing bed; the plants are easy to grow, and they grow quite quickly. Seeds germinate in 2–3 weeks, and plants start to flower in 10–12 weeks after sowing. If toddlers get tired of admiring the flowers and decide to eat them instead, they are in no danger – both flowers and leaves are edible. Young children are often fascinated by the way water balls on the leaves, like globules of mercury.

The leaves are rounded, shield-shaped with the petiole in the centre. The flowers have 5 or more petals, an ovary with 3 carpels, and an infundibuliform nectar tube in the back. Nasturtiums are self-seeding, and often pop up in places where they are not wanted. Garden escapees are found in bushland and nature reserves in many parts of coastal eastern Australia. I have often seen them growing wild on my walks around the shores of Sydney Harbour. They are good companion plants, excreting a strong pungent essence into the air and soil, which helps to deter aphids, white-fly and root pests, and the essence secreted into the soil is also absorbed by other plants close by, helping them to resist being attacked by those pests.

All parts of the plant are edible. The leaves have a pungent peppery taste, while the flowers are milder in flavour. The hot, pungent seeds can also be eaten. If the end of the spur is pinched off, the sweet nectar can be sucked. The nasturtium is rich in vitamin C, iron and other minerals, and also has a natural antibiotic action that is fast-working in the body. Some people pick the seeds or the flower buds and pickle them in vinegar to use as a condiment, similar to capers. Pricking the seeds with a fork before adding the vinegar helps the vinegar to penetrate the seeds, and helps to preserve them. Mature seeds can be dried and ground for use as a pepper substitute. Flowers and leaves can be used in dips, spreads and cream cheese for added flavour and visual appeal. The flowers also make a pretty garnishing for salad.

A tea can be made from an infusion of the leaves and used for the treatment of chest infections. If a little liquid soap is added to the infusion, it makes an effective spray against aphids.

Information about medicinal qualities of plants, or about their use as medicines, is for interest only, and is not intended to be used as a guide for the treatment of medical conditions.